This is a completely rewritten scsipi_xfer execution engine, and the
associated changes to HBA drivers. Overview of changes & features:
- All xfers are queued in the mid-layer, rather than doing so in an
ad-hoc fashion in individual adapter drivers.
- Adapter/channel resource management in the mid-layer, avoids even trying
to start running an xfer if the adapter/channel doesn't have the resources.
- Better communication between the mid-layer and the adapters.
- Asynchronous event notification mechanism from adapter to mid-layer and
peripherals.
- Better peripheral queue management: freeze/thaw, sorted requeueing during
recovery, etc.
- Clean separation of peripherals, adapters, and adapter channels (no more
scsipi_link).
- Kernel thread for each scsipi_channel makes error recovery much easier
(no more dealing with interrupt context when recovering from an error).
- Mid-layer support for tagged queueing: commands can have the tag type
set explicitly, tag IDs are allocated in the mid-layer (thus eliminating
the need to use buggy tag ID allocation schemes in many adapter drivers).
- support for QUEUE FULL and CHECK CONDITION status in mid-layer; the command
will be requeued, or a REQUEST SENSE will be sent as appropriate.
Just before the merge syssrc has been tagged with thorpej_scsipi_beforemerge
without MII. It supports 100BaseTX only. Half duplex/Full duplex can
be specified manually, but there are no auto negotiation functionality.
XXX: It takes 34 seconds before sending/receiving packets on the wire
after initial setup. It is obviously a bug because the board
just works fine on NEWS-OS, but I cannot find what's wrong...
Once it starts working, it seems there are no problems.
for each driver to indicate the interrupt has been handled or not.
add prototype of apbus_dmatag_init() function, which allocates memory
and initialize its member including bus space handle to flush DMA write
cache. Note that the allocated pointer must be freed.
Clear interrupt mask for specified interrupt in apbus_intr_establish().
Add dma stuff; define apbus_dmamap_sync() to flush DMA write cache by
accessing the corresponding I/O port.
wiz